Hi @CarlK - I’m not clear what you mean by “ I’ve been able to access app in builder for years”….I’ve never heard of or seen your error message before and I’m a full time builder.
I’d recommend reaching out to support@knack.com so they can investigate for you.
I agree, I’ve had apps up and running with no issues for years, made the transitions as Knack versions changed, etc. Then all of the sudden I start getting this error and can’t access the apps in builder. They function like they are supposed to live, but I can’t edit them or see records, etc. I’ve reached out to support earlier today, have not heard back. Was hoping someone else may have run across the issue. It’s happening on two different computers using different browsers.